# Polarization Using Sunglasses and a Computer Screen

Using a pair of polarizing sunglasses, you can demonstrate the effects of polarization together with a computer screen which is also polarizing. When the axes of polarization of the two polarizing screens are rotated, the brightness alternates between bright and dark.

Light coming from a computer screen is usually polarized. In the video below, when polarized light passes through another polarizer, the intensity of the light is given by Malus' law:

$I = I_o cos ^2{\theta}$

where $\theta$ is the angle between the two axes of polarization and $I_o$ is the original intensity of the unpolarized light.

Only the components of electric field vectors in electromagnetic radiation that are parallel to the axis of polarization of a polarizing filter will be permitted through. Those electric field components that are perpendicular to the polarization axis are blocked by the filter.

Hence, the amplitude of a vector A that passes through is given by $A = A_o \cos{\theta}$. Since intensity is proportional to the square of amplitude ($I \propto {A^2}$), we have Malus' law.

The purpose of having polarizing filters in sunglasses and computer screens is to cut out glare due to light from other sources.

https://physicslens.com/polarization-using-sunglasses-and-a-computer-screen/

This site uses Akismet to reduce spam. Learn how your comment data is processed.